The purpose of this study was to describe the anatomy and characterize the biomechanics of the posterolateral aspect of the canine knee. Ten adult canine knees were each used for anatomy and biomechanical testing. Distances and motion limits were measured using a 6 degree-of-freedom electromagnetic tracking system. Canine knee dissection reproducibly identified structures present in the human posterolateral knee. The course and attachment sites of the fibular collateral ligament, popliteofibular ligament, and popliteus tendon were similar to human anatomy. Sequential sectioning of the fibular collateral ligament, popliteofibular ligament, and popliteus tendon all significantly increased varus translation at full extension, 60 degrees , and 90 degrees of knee flexion. Sectioning of the fibular collateral ligament significantly increased external rotation at flexion angles near full extension, while popliteus tendon sectioning also significantly increased external rotation at 90 degrees of knee flexion. Based on the fact that the anatomy of the fibular collateral ligament, popliteus tendon, popliteofibular ligament, and the biomechanical properties of the canine posterolateral knee are similar to the human knee, we believe the canine knee is a suitable model to study the natural history of posterolateral knee injuries. The canine model will also prove valuable in the validation of reconstruction techniques and studying the potential development of medial compartment osteoarthritis following posterolateral knee injuries.